#include <iostream>

unsigned DoIt(unsigned n)
{
	if (n < 2)
		return n;
	
	unsigned ret_val = 0;
	for (unsigned i = 1; i <= n / 2; ++i)
		ret_val += DoIt(i);
	
	return ret_val + 1;
}

int main()
{
	unsigned n;

	std::cin >> n;

	std::cout << DoIt(n);

	return 0;
}